Determination of Pipe Size in Water Supply Scheme
What is the problem in determining the size of the supply main in a water supply scheme?
The problem involves the determination of the size of a supply main for a water supply scheme to be designed for serving a population of 4 lakhs, where the storage reservoir is situated at 8 km away from the town, and the loss of head from the source to the city is 16 metres.
What are the factors considered in calculating the size of the supply main using Weisbach formula and Hazen William formula?
The key factors considered are the coefficient of friction for the pipe material and the net head available in the system.
Answer:
The size of the pipe cannot be determined as the velocity of flow is zero for both the Weisbach formula and Hazen William formula. This indicates that there will be no flow of water in the pipe due to the negative net head available in the system.
In the scenario provided, the calculation of the size of the supply main using both the Weisbach formula and Hazen William formula resulted in a zero velocity of flow, indicating no water flow in the pipe. This is due to the net head available being negative, making it impossible to determine the size of the pipe.
The Weisbach formula utilizes the coefficient of friction for the pipe material to determine the frictional head loss, while the Hazen William formula considers the coefficient of Hazen Williams for the same purpose. However, in this case, both formulas lead to the same conclusion of zero flow.
It is essential to ensure positive net head available in a water supply system to facilitate the flow of water through the pipes. Any negative net head can impede the flow and render it impossible to determine the size of the supply main.